An innovative and easily implemented technique in which nanoscale elements precisely assemble themselves over large surfaces could soon open doors to dramatic improvements in the data storage capacity of electronic media, according to scientists at the University of California, Berkeley, and the University of Massachusetts Amherst (UMass Amherst).
"I expect that the new method we developed will transform the microelectronic and storage industries, and open up vistas for entirely new applications," said co-lead investigator Thomas Russell, director of the Materials Research Science and Engineering Center at UMass Amherst, visiting Miller Professor at UC Berkeley's Department of Chemistry, and one of the world's leading experts on the behavior of polymers. "This work could possibly be translated into the production of more energy-efficient photovoltaic cells, for instance."

Russell conceived of this new approach with co-lead investigator Ting Xu, a UC Berkeley assistant professor with joint appointments in the Department of Material Sciences and Engineering and the Department of Chemistry. They describe their work in the Feb. 20 issue of the journal Science.

"The density achievable with the technology we've developed could potentially enable the contents of 250 DVDs to fit onto a surface the size of a quarter," said Xu, who is also a faculty scientist at Lawrence Berkeley National Laboratory.

Xu explained that the molecules in the thin film of block copolymers - two or more chemically dissimilar polymer chains linked together - will self-assemble into an extremely precise, equidistant pattern when spread out on a surface, much like a regiment of disciplined soldiers lining up in formation. For more than a decade, researchers have been trying to exploit this characteristic for use in semiconductor manufacturing, but they have been constrained because the order starts to break down as the size of the area increases.

Once the formation breaks down, the individual domains cannot be read or written to, rendering them useless as a form of data storage.

To overcome this size constraint, Russell and Xu conceived of the elegantly simple solution of layering the film of block copolymers onto the surface of a commercially available sapphire crystal. When the crystal is cut at an angle - a common procedure known as a miscut - and heated to 1,300 to 1,500 degrees Centigrade (2,372 to 2,732 degrees Fahrenheit) for 24 hours, its surface reorganizes into a highly ordered pattern of sawtooth ridges that can then be used to guide the self-assembly of the block polymers.

With this technique, the researchers were able to achieve defect-free arrays of nanoscopic elements with feature sizes as small as 3 nanometers, translating into densities of 10 terabits per square inch. One terabit is equal to 1 trillion bits, or 125 gigabytes.

Because crystals come in a variety of sizes, there are few limitations to how large this block copolymer array can be produced, the researchers said. They also noted that the angle and depth of the sawtooth ridges can be easily varied by changing the temperature at which the crystal is heated to fine tune the desired pattern.

"We can generate nearly perfect arrays over macroscopic surfaces where the density is over 15 times higher than anything achieved before," said Russell. "With that order of density, one could get a high-definition picture on a screen the size of a JumboTron."

"It's one thing to get dozens of soldiers to stand in perfect formation in an area the size of a classroom, each person equidistant from the other, but quite another to get tens of trillions of individuals to do so on the field in a football stadium," Xu added. "Using this crystal surface as a guide is like giving the soldiers a marker so they know where to stand."

Other research teams across the country are engaged in similar efforts to break the size barrier of self-assembled block copolymers, but this new project by the UMass Amherst-UC Berkeley scientists differs in that it does not rely upon advances in lithography to achieve its goals.

In the semiconductor industry, optical lithography is a process in which light passes through a mask with a desired circuit pattern onto a photosensitive material, or photoresist, that undergoes a chemical change. Several steps of chemical treatment are then used to develop the desired pattern for subsequent use.

To keep up with Moore's Law and the demand for increasingly smaller features for semiconductors and microprocessors, industry has turned to nanolithography and the use of ever-shorter wavelengths of light at greater cost.

"The challenge with photolithography is that it is rapidly approaching the resolution limits of light," said Xu. "In our approach, we shifted away from this 'top down' method of producing smaller features and instead utilized advantages of a 'bottom up' approach. The beauty of the method we developed is that it takes from processes already in use in industry, so it will be very easy to incorporate into the production line with little cost."

An added benefit, said Xu, is that "our technique is more environmentally friendly than photolithography, which requires the use of harsh chemicals and acids."

UC Berkeley and UMass Amherst have filed a joint patent on this technology.

The U.S. Department of Energy and the National Science Foundation helped support this research.

Is this the same as 3D volume holographic optical storage nanotechnology ? Is it some kind of plasmonic nanolithography ? I think Lex Luthor made sure he is in possession of all the big Crystals.

All these technologies are old news, but with modern technology evolving and manufacturing costs go down as machine prices go down, just helps brings everything closer . . . Like the 250Tb hdd's i anxiously await.

What do you want a 250 TB HDD for? The only possible use of so much storage would be for some seriously large amounts of HD video.

Click to expand...

Theirs about a million reasons, servers (of all kinds) web servers, data servers, photograph storage (professional photographers go through TB of data like its nothing.) Video storage(if you backup full DVD's to your hard drive it can take up some serious room) BEYOND HD will come soon the world is not going to stop at 1080 HD resolutions, it will easily go beyond! Hard drives limit speeds of most computers, its the weak link(since its mechanical) that video editors talk about this all the time, so the more advancements in HD technologies the better off everything else will be.

Also just to mention a downside to this, research like this HAPPENS allllll the time. Their are huge breakthroughs but getting them to the market can be very very difficult. Anyone remember MRAM (magnetic ram), their was a big to do about it quite a while back, but since then we haven't herd much of it, as well as with holographic storage its still for the most part in the Dark. Often people with PHds just dont know how to get their amazing technological breakthroughs effectively utilized by businesses and consumers. You can have the best technological advancement since sliced bread, but if no one can use it, its worth as much as dirt. And making some of these technologies useful is still very very difficult.

You only need one reason for so much storage that reason is high quality pr0n

no, seriously though. Its this kind of R&D which could make SSD high capacity right? Will it make longevity any better though? All the mention of not needing to use so much chemical in the fabrication process must be good for the media right?

Ive never played an online multiplayer game and not record myself (eventually i encode the footage). Recording at 100 frames a second ( to not compromise my gameplay too much ), 20 minutes of footage can equate to 80Gb of space. A couple of day play and im destined to fill the largest of current hard drives.

I encode very very often so that space is made available asap, but that only makes room for photoes and video's. I never decrease the quality/size of digital photoes, nor would i do it to any of the digital video footage. Qwerty_Lesh always has to right on the money ofcourse.

Thats 3 of about 10 million reasons for hdd space. Theres no real reason why i selected the 250Tb beyond knowing that ill still be alive when that technology is created (Unless i dont die of old age), having said that, i have no doubt it will grow to much much bigger. 100Tb seems to be a meer 3-5 years away from reaching mainstream.